The remelting and solidification of turbine blade samples within the scope of the D 2 mission

Abstract In the scope of the German D 2 mission, samples of a nickel super alloy CMSX 6 were remelted and solidified. The sintered sample material contained a strengthening dispersion of Al 2 O 3 particles with a grain size of approximately 50 nm. Reference samples consisted of the cast material without particles. The samples shape was similar to small turbine blades. In order to preserve their geometry the samples were provided with a thin ceramic mold skin. The main objectives of the experiments were the shape preservation by means of the skin and informations on the particles behaviour. The local and the chronological temperature profile was evaluated by computer simulation additionally to the ground lab runs. Both results showed a good consistency. The results of the flight experiments were influenced by the formation of gas cavities in the samples processed from the powdery condition. Corresponding to the calculated results the melting boundary was detected in all samples exactly in the predicted position. The particle showed a distinct tendency to agglomeration. The ceramic mold skin fulfilled its task, e.g. the reliable enclosure of the melt, in spite of the considerably bulged samples.